What causes prooflike MS coins to be prooflike?
XpipedreamR
Posts: 8,059 ✭✭
Is it the planchet? the die? all of the above? some of the above?
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The Ludlow Brilliant Collection (1938-64)
Yea, this is what I've always thought/been told. The mirror like fields are due to the fact that the die has not made enough strikes for the die flow lines to begin developing. As more strikes are made, the metal flow produces die flow lines which in turn are what cause the fields to have cartwheel luster finishes instead of mirror like finishes.....I think I understand it better than I can explain it....
Greg Hansen, Melbourne, FL Click here for any current EBAY auctions Multiple "Circle of Trust" transactions over 14 years on forum
Randy Campbell's DMPL Morgan Dollar Article
Part II:
No more than one or two percent of all Morgan dollars exhibit mirror surfaces on both sides of the coin. What caused these mirror surfaces? How did Prooflike, Deep Mirror Prooflike, and Ultra Deep Mirror dollars come into existence?
In his definitive Morgan and Peace Dollar Textbook, author Wayne Miller, listed several causes (pp. 64 ff.) for the existence of mirror surface dollars. Among the causes listed by Miller:
THE MASTER DIE WAS A CAMEO:
It is believed that the master die for the Morgan series had cameo mirror surfaces. The design elements, such as Liberty’’s head and the eagle, had frosty white surfaces while the fields of the master die had deeply mirrored surfaces. This cameo appearance was then transferred to the working hubs and then to the working dies used to strike dollars. This cameo prooflike effect would be transferred to the first 500 - 2,000 coins from a given working die before the cameo faded and disappeared. All subsequent dollars struck from that die (perhaps 50,000 to 100,000 coins) would NOT have cameo prooflike surfaces. In most cases these non-prooflike dollars would exhibit frosty or satiny luster.
POLISHING OUT CLASH MARKS:
Sometimes during the striking process a blank planchet failed to feed into the striking press. in this situation, the obverse die and the reverse die would come into contact with each other. This would result in some of the obverse die design being transferred to the fields of the reverse die, and vice versa. This process is known as ““clashed dies.””Mint employees would attempt to polish out the clash marks. The polishing process would result in a mirror surface on the die over its entire surface. The next few hundred coins struck from this polished die would evidence mirror surfaces minus the cameo effect. Such dollars are referred to as brilliant mirror surface dollars or brilliant P-L’’s.Miller lists several other causes for mirror surface Morgan dollars. Those with a strong interest in this topic are urged to read the appropriate chapter in his Morgan and Peace Dollar Textbook which, unfortunately, is out of print and seldom available.
Stuart
Collect 18th & 19th Century US Type Coins, Silver Dollars, $20 Gold Double Eagles and World Crowns & Talers with High Eye Appeal
"Luck is what happens when Preparation meets Opportunity"
may not affect all series, and few PL coins will exhibit all these.
The most typical is simply a first strike from a new die, especially if the fields
have been flattened (basined). These coins will exhibit a sort of "frost" from
the imperfections in die. They also can appear PL because of die polishing or
planchet polishing. Generally it requires a nice full strike to make any of these
look PL but this isn't always necessary. Since the PL effect fades as the dies
wear then PL's are typically from relatively new dies.
"Seu cabra da peste,
"Sou Mangueira......."
(sorry, my attempt at a russ-like sarcasm answer)
i've found many Jeffersons that exhibit this quality with 1998 and 1957 being two dates that come to mind if for no other reason than they're the best i've found. they almost look like branch mint proofs.
al h.